Updated fermentation process may boost biofuel production

Rising concern about the release of carbon into the atmosphere has led to renewed efforts to develop advanced biofuels for transportation. Synthesized from the sugars in the lignocellulosic biomass of grasses and other non-food plants, and produced in a sustainable manner, advanced biofuels could be carbon-neutral, meaning their use would not add excess carbon to the atmosphere.

Clostridium acetobutylicum—also known as the Weizmann organism after Chaim Weizmann, the chemist who first used the bacterium to ferment ABE products from starch—was used by the British in World War I to ferment acetone for the production of cordite. The process was used until the 1950s, when it was replaced by cheaper petrochemical-based processes.

From left, Harvey Blanch, Dean Toste and Douglas Clark led a research team that integrated biological fermentation with chemical catalysis to upgrade simple carbon chains into potential fuel molecules.

Credit: Roy Kaltschmidt/Berkeley Lab

"While there has been some progress in engineering microbes to produce advanced biofuels, the quantities produced thus far—technically, the solution's titer—tend to be very limited," said Harvey Blanch, co-author of the paper who also holds joint appointments with Berkeley Lab and UC Berkeley. "A hybrid method, combining microbial production with chemical catalysis, might provide a pathway to more efficient production of these advanced biofuels."

Toste believes the combination of biological fermentation and chemical catalysis has important potential applications beyond the conversion of lignocellulosic biomass into transportation fuels and could become a powerful new technology-enabling tool.

"Many technologies today rely on either fermentation or chemical catalysis," Toste said. "The idea of building integrated fermentation processes involving networks of catalysts is an exciting prospect."
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